The present invention relates to solid freeform fabrication and, more particularly, to a solid freeform fabrication using a plurality of modeling materials.
Solid Freeform Fabrication (SFF) is a technology enabling fabrication of arbitrarily shaped structures directly from computer data via additive formation steps. The basic operation of any SFF system consists of slicing a three-dimensional computer model into thin cross sections, translating the result into two-dimensional position data and feeding the data to control equipment which fabricates a three-dimensional structure in a layerwise manner.
Solid freeform fabrication entails many different approaches to the method of fabrication, including three-dimensional printing, electron beam melting, stereolithography, selective laser sintering, laminated object manufacturing, fused deposition modeling and others.
In three-dimensional printing processes, for example, a building material is dispensed from a dispensing head having a set of nozzles to deposit layers on a supporting structure. Depending on the building material, the layers may then be cured or solidified using a suitable device. The building material may include modeling material, which forms the object, and support material, which supports the object as it is being built. Various three-dimensional printing techniques exist and are disclosed in, e.g., U.S. Pat. Nos. 6,259,962, 6,569,373, 6,658,314, 6,850,334, 6,863,859, 7,183,335 7,209,797, 7,300,619 and 7,225,045 and U.S. Published Applications Nos. 20050104241 and 20060054039, all of the same Assignee, the contents of which are hereby incorporated by reference.
Solid freeform fabrication is typically used in design-related fields where it is used for visualization, demonstration and mechanical prototyping. Thus, SFF facilitates rapid fabrication of functioning prototypes with minimal investment in tooling and labor. Such rapid prototyping shortens the product development cycle and improves the design process by providing rapid and effective feedback to the designer. SFF can also be used for rapid fabrication of non-functional parts, e.g., for the purpose of assessing various aspects of a design such as aesthetics, fit, assembly and the like. Additionally, SFF techniques have been proven to be useful in the fields of medicine, where expected outcomes are modeled prior to performing procedures. It is recognized that many other areas can benefit from rapid prototyping technology, including, without limitation, the fields of architecture, dentistry and plastic surgery where the visualization of a particular design and/or function is useful.
Although numerous improvements and different approaches which have been developed over the years for solid freeform fabrication, the number of techniques which allow the additive formation of objects using more than one modeling material is limited.
U.S. Pat. No. 5,149,548 of Yamane et al., for example, discloses a three-dimensional printing technique using two-part curable material. The material is jetted from an ink jet head to a stage and laminated thereon. The ink jet head is disposed under the stage, such that the two-part curable material is jetted from a downward side to an upward side and is cured every jetting process. The apparatus may include several inkjet nozzles and the two-part curable material can be exchanged for another during the process. Since the jetting is from a downward side to an upward side, a newly-exchanged two-part curable material is not mixed or combined with the previously-used two-part curable material.
U.S. Pat. No. 6,508,971 of Leyden et al., discloses a technique for creating a three-dimensional object by depositing a build material on a working surface from a plurality of dispensing orifices in a print head. The build material is selectively dispensed from the print head while scanning the working surface. Subsequently, the print head is repositioned and the scan is repeated along a path which is offset from the previous path. The scans are repeated until the three-dimensional object is formed. The disclosure contemplates the use of different materials on different raster lines or drop locations.
U.S. Pat. No. 6,658,314 of Gothait et al. and incorporated herein by reference, discloses a printing system and a method for printing complex three-dimensional models utilizing two dispensing heads which eject building material. A “modeling” material is dispensed from a dispensing head, and a “support” material is dispensed from a second dispensing head. The two materials may be combined to produce layers for forming the three-dimensional model, while a different combination is used to build the support structure or the release structure.
The two building materials may have different hardness characteristics so as to control the hardness of the layers. The construction layers of the model are formed with a harder modulus of elasticity than the release layers.
U.S. Pat. No. 7,300,619, of the present Assignee, the contents of which are hereby incorporated by reference, discloses apparatus for management and control of the supply of building materials to three-dimensional printing systems. A supply system having a set of valves or a valve matrix is used for controlling the supply. Management and control of materials are achieved by measuring data on the status of building material in the printing cartridge or the supply system, and processing the building material status data to determine parameters of the building material. The supply system can include several cartridges each containing one type of building material, either modeling material or support material. Different cartridges can contain different types of materials and colors.
U.S. Published Application No. 20040187714 of the same Assignee specifies use of modeling materials having different properties, in different combinations, in order to obtain different regions, forming a homogeneous or non-homogeneous three-dimensional structure in which different regions may be structurally different, chemically different or have different properties. The different combinations comprise composite materials having properties that vary within the material.
U.S. Published Application No. 20060159869 of Kramer et al., discloses a solid freeform fabrication technique in which two reactive build compositions which include the same material property but with different attributes (typically, one composition is mechanically flexible while the other is mechanically rigid), are dispensed onto a substrate to form a mixed composition. The mixed composition is subsequently cured to form a layer of cured composition, which includes the same material property but with an attribute which differs from, and depends upon the respective amounts of each of the individual attributes of the dispensed compositions. The disclosure also contemplates the solid freeform fabrication of three-dimensional objects having regions which vary in the material property.
U.S. Pat. No. 7,500,846 of the present Assignee, the contents of which are hereby incorporated by reference, teaches the use of one or more types of photopolymers dispensed separately or together, simultaneously or consecutively.
U.S. Pat. No. 6,989,115 (Russell et al.) discloses a three-dimensional printer including multiple printheads for printing binder and/or colorant onto a bed of build material in a build chamber. The printer can include determining the total amount of binder liquid needed to solidify the build material at the particular location, determining the amount of each of the colored binder liquids needed to produce the desired color at the particular location and determining the amount of colorless binder liquid that needs to be added to the colored binder liquids to obtain the predetermined total binder liquid requirement.